The present invention relates to a structure for mounting a printed board, in which a multiplicity of printed boards (sub substrates), which are juxtaposed to each other, are connected and mounted to a main printed board that is secured to a backboard, each of the printed boards including an electronic part area on which a plurality of electronic parts are mounted, and a semiconductor device area on which a plurality of semiconductor devices are mounted. The present invention also relates to an electronic apparatus (for example, a nuclear medicine diagnosis system having an observation unit such as a PET (Positron Emission Tomography) system and a SPECT (Single Photon Emission Computer Tomography) system) having the structure for mounting a printed board.
Conventional structures for mounting a printed board are known by JP-A-2001-7572 (patent document 1) and JP-A-11-186708 (patent document 2). According to the patent document 1, when a plurality of printed boards are mounted inside a case whose printed board entrance is opened, a pair of guide rails for guiding a pair of edges of each printed board, which are opposed to each other, are attached in rows in the case of an electronic apparatus so that the pair of guide rails are opposed to the case. Here, the distance from a start point of the pair of guide rails to the entrance of the printed board differs from one another; and the edges of a rail member constituting the guide rail, on the start point side, expand in a direction in which the edges are spaced away from each other. In addition, according to the patent document 2, in a mounting method for mounting a printed board relating to electric parts that require electromagnetic shielding, soldering paste is applied to the printed board, and then the electric parts are mounted on the printed board. Moreover, a shield case is attached on the printed board. The shield case has a box shape whose bottom is opened to cover the electric parts from the top, and is provided with the clearance between the shield case and the printed board at a plurality of points. Then, hot air is put into the clearance at least at one of the points, and the hot air is then exhausted from the clearance at least at another point, and thereby the electric parts and the shield case are soldered with the soldering paste.
On the other hand, a PET (Positron Emission Tomography) system, which is electronic apparatus having a plurality of unit substrates each including semiconductor devices that are mounted in matrix, is known by JP-A-2005-106805 (patent document 3). The patent document 3 discloses a nuclear medicine diagnosis system such as a PET system. The PET system includes a support member, and a plurality of detector units that are attached to the support member in a manner that the detector units can be freely removed. Each of the detector units includes a housing member, and a plurality of unit substrates that are housed in the housing member in a manner that the unit substrates can be freely removed. Each of the unit substrates includes a first substrate and a second substrate. The first substrate includes a plurality of semiconductor radiation detectors, each of which detects a radioactive ray generated by chemical solution that has been injected into the body of a subject. The second substrate includes an integrated circuit for processing a radioactive-ray detection signal that is output from each of the multiplicity of semiconductor radiation detectors. The integrated circuit includes: an analog integrated circuit for processing a signal output from the semiconductor radiation detector; an A/D converter for converting an analog signal, which is the output of the analog integrated circuit, into a digital signal; and a digital integrated circuit for inputting a signal output from the A/D converter. The PET system further includes a counting device that inputs each output from the integrated circuit, and that calculates in pairs the output corresponding to a pair of radioactive-ray detection signals detected during the setup time. The PET system creates tomogram information by use of calculation information output from the counting device.